stringr 0.6
===========

* new modifier `perl` that switches to Perl regular expressions

* `str_match` now uses new base function `regmatches` to extract matches -
  this should hopefully be faster than my previous pure R algorithm

stringr 0.5
===========

* new `str_wrap` function which gives `strwrap` output in a more convenient
  format

* new `word` function extract words from a string given user defined
  separator (thanks to suggestion by David Cooper)

* `str_locate` now returns consistent type when matching empty string (thanks
  to Stavros Macrakis)

* new `str_count` counts number of matches in a string.

* `str_pad` and `str_trim` receive performance tweaks - for large vectors this
  should give at least a two order of magnitude speed up

* str_length returns NA for invalid multibyte strings

* fix small bug in internal `recyclable` function

stringr 0.4
===========

 * all functions now vectorised with respect to string, pattern (and
   where appropriate) replacement parameters
 * fixed() function now tells stringr functions to use fixed matching, rather
   than escaping the regular expression.  Should improve performance for 
   large vectors.
 * new ignore.case() modifier tells stringr functions to ignore case of
   pattern.
 * str_replace renamed to str_replace_all and new str_replace function added.
   This makes str_replace consistent with all functions.
 * new str_sub<- function (analogous to substring<-) for substring replacement
 * str_sub now understands negative positions as a position from the end of
   the string. -1 replaces Inf as indicator for string end.
 * str_pad side argument can be left, right, or both (instead of center)
 * str_trim gains side argument to better match str_pad
 * stringr now has a namespace and imports plyr (rather than requiring it)

stringr 0.3
===========

 * fixed() now also escapes |
 * str_join() renamed to str_c()
 * all functions more carefully check input and return informative error
   messages if not as expected.
 * add invert_match() function to convert a matrix of location of matches to
   locations of non-matches
 * add fixed() function to allow matching of fixed strings.

stringr 0.2
===========

 * str_length now returns correct results when used with factors
 * str_sub now correctly replaces Inf in end argument with length of string
 * new function str_split_fixed returns fixed number of splits in a character
   matrix
 * str_split no longer uses strsplit to preserve trailing breaks
