Log Message:
Update libestr to 0.1.10.

- changed some functions that don't modify their arg to take const arg
- bugfix: str2num did not convert hex values correctly
- bugfix: problems with trailing incomplete hex sequence
- bugfixes to StrFromNumber
- some checks for potential overflows with giantic strings (>2GB)
- lower autotools requirement to 2.59 permits to build on stock RHEL/CENTOS 5