Log Message:
Update php-excel to 1.8.1.

2015-04-30 (v1.8.1):
- Bugfix:   (goncons)         Work Item GH-397  - Fix for Writing an Open \ 
Document cell with non-numeric formula
- Bugfix:   (sarciszewski)    Work Item GH-329  - Avoid potential divide by zero \ 
in basedrawing
- Bugfix:   (ymaerschalck)    Work Item GH-405  - XML External Entity (XXE) \ 
Processing, different behaviour between simplexml_load_string() and \ 
simplexml_load_file().
- Bugfix:   (MBaker)                            - Fix to ensure that current \ 
cell is maintained when executing formula calculations
- Bugfix:   (MBaker)          Work Item GH-350  - Keep/set the value on Reader \ 
_loadSheetsOnly as NULL, courtesy of Restless-ET
- Bugfix:   (MBaker)          Work Item CP18105 - Loading an Excel 2007 \ 
spreadsheet throws an "Autofilter must be set on a range of cells" \ 
exception
- Bugfix:   (MBaker)          Work Item GH-388  - Fix to autoloader registration \ 
for backward compatibility with PHP 5.2.0 not accepting the prepend flag
- Bugfix:   (MBaker)          Work Item GH-384  - DOM loadHTMLFile() failing \ 
with options flags when using PHP < 5.4.0
- Bugfix:   (MBaker)                            - Fix for percentage operator in \ 
formulae for BIFF Writer
- Bugfix:   (MBaker)                            - Fix to getStyle() call for \ 
cell object
- Bugfix:   (MBaker)                            - Discard Autofilters in \ 
Excel2007 Reader when filter range isn't a valid range
- Bugfix:   (frozenstupidity) Work Item GH-423  - Fix invalid NA return in VLOOKUP
- Bugfix:   (wiseloren)       Work Item CP21454 - "No Impact" \ 
conditional formatting fix for NumberFormat
- Bugfix:   (bobwitlox)       Work Item GH-467  - Bug in Excel2003XML reader, \ 
parsing merged cells
- Bugfix:   (MBaker)          Work Item GH-302  - Fix for CEIL() and FLOOR() \ 
when number argument is zero
- Bugfix:   (MBaker)                            - Remove cells cleanly when \ 
calling RemoveRow() or RemoveColumn()
- General:  (MBaker)                            - Small performance improvement \ 
for autosize columns
- General:  (frost-nzcr4)     Work Item GH-379  - Change the getter/setter for \ 
zeroHeight to camel case
- General:  (MBaker)          Work Item GH-394  - DefaultValueBinder is too much \ 
aggressive when converting string to numeric
- General:  (MBaker)                            - Default precalculate formulas \ 
to false for writers
- General:  (MBaker)                            - Set default Cyclic Reference \ 
behaviour to 1 to eliminate exception when using a single cyclic iteration in \ 
formulae
- General:  (MBaker)          Work Item GH-396  - Some Excel writer libraries \ 
erroneously use Codepage 21010 for UTF-16LE
- Feature:  (WiktrzGE)        Work Item GH-404  - Methods to manage most of the \ 
existing options for Chart Axis, Major Grid-lines and Minor Grid-lines
- Feature:  (frost-nzcr4)     Work Item GH-403  - ODS read/write comments in the cell
- Feature:  (CQD)             Work Item GH-389  - Additional Mac CJK codepage \ 
definitions
- Feature:  (bolovincev)      Work Item GH-269  - Update Worksheet.php \ 
getStyleByColumnAndRow() to allow a range of cells rather than just a single \ 
cell
- Feature:  (MBaker)                            - New methods added for testing \ 
cell status within merge groups
- Feature:  (cifren/MBaker)   Work Item GH-205  - Handling merge cells in HTML Reader
- Feature:  (MBaker)                            - Helper to convert basic HTML \ 
markup to a Rich Text object
- Feature:  (MBaker)                            - Improved Iterators
                                                    New Column Iterator
                                                    Support for row and column ranges
                                                    Improved handling for next/prev
- Security: (MBaker)                            - XML filescan in XML-based \ 
Readers to prevent XML Entity Expansion (XEE)
                                                    (see \ 
http://projects.webappsec.org/w/page/13247002/XML%20Entity%20Expansion for an \ 
explanation of XEE injection) attacks
                                                  Reference CVE-2015-3542 - \ 
Identification of problem courtesy of Dawid Golunski (Pentest Ltd.)