Log Message:
Update to 0.11.0

Upstream changes:
Changed in xts 0.11-0:

o  Fix make.index.unique() to always return a unique and sorted index. Thanks
   to Chris Katsulis for the report and example (#241).

o  Add window.xts() method and completely refactor the internal binary search
   function it depends on. Thanks to Corwin Joy for the PR, tests, review, and
   patience (#100, #240).

o  Better axis tick mark locations for plots. Thanks to Dirk Eddelbuettel for
   the report (#246). Also incorporate axTicksByTime2() into axTicksByTime() to
   reduce code duplication from the migration of quantmod::chart_Series() to
   xts::plot.xts() (#74).

o  Add details to plot.xts() parameters that are periodicity, now that RStudio
   has argument completion. Thanks to Evelyn Mitchell for the PR (#154).

o  periodicity() now warns instead of errors if the xts object contains less
   than 2 observations (#230).

o  first() and last() now keep dims when they would otherwise be dropped by a
   regular row subset. This is consistent with head() and tail(). Thanks to
   Davis Vaughan for the report (#226).

o  Fix subset when ISO8601 string is outside the valid range, so it returns no
   data instead of all rows (#96).

o  Avoid partial name matches from parse.side() (inside .parseISO8601())
   results that are passed to firstof() and lastof(). Thanks to @gp2x for the
   report and the patch (#231).

o  na.locf.xts() now loops over columns of multivariate objects in C code,
   instead of in R. This should improve speed and memory performance. Thanks to
   Chris Katsulis and Tom Andrews for their reports and patches (#232, #233,
   #234, #235, #237).

o  Change plot.xts() default 'pch = 0' (rectangles) to 'pch = 1' (circles) so
   it looks more like base and zoo plots (#203).

Changed in xts 0.10-2:

o  na.locf.xts() and na.omit.xts() now support character xts objects. Thanks to
   Ken Williams and Samo Pahor for the reports (#42).

o  na.locf.xts() now honors 'x' and 'xout' arguments by dispatching to the next
   method (#215). Thanks to Morten Grum for the report.

o  coredata.xts() now functions the same as coredata.zoo() on zero-length
   objects, and only removes xts-related attributes (#223). Thanks to Vincent
   Guyader for the report.

o  plot.xts() no longer ignores 'col.up' and 'col.dn' when 'type="h"' \ 
(#224).
   Thanks to Charlie Friedemann for the report. This was inadvertently broken
   as part of the fix for #210.