character_limiter now works correct for UTF-8 strings

strlen() doesn't return the actual length for unicode strings. For example strlen('سلام') returns 8, but length of سلام is 4. strlen(utf8_decode('سلام')) returns correct value 4.
Reference: http://www.php.net/manual/de/function.strlen.php#45407
removed newline from end of file
remove newline from end of file
count number of characters (with mb_strlen) instead of counting number of bytes with strlen
Merge remote-tracking branch 'asli/develop' into patch-1
Allow updating all properties for an item.
[ci skip] Test fixes
Fixed code style & added few extra checks.
Updated cart documentation.
Delete by values, not keys
Introducing compatibility layers

 - Limited support for mbstring (mb_strlen(), mb_strpos(), mb_substr() only) via iconv.
   Falls back to regular strlen(), strpos(), substr() if iconv is not available.
 - Password hashing, dependant on CRYPT_BLOWFISH (2y version, available since PHP 5.3.7) availability.
Merge pull request #2610 from mjnaderi/patch-1

character_limiter now works correct for UTF-8 strings
Update Text and Inflector helpers to utilize mbstring, if available

Text: word_wrap(), ellipsize()
Inflector: humanize(), underscore() (rel #2855)
Added changelog entry.
An example to the docs.
Tidy code a little bit.
Fix syntax error
Re-arranged documentation, fixed comment.
Added Missing new line.
Merge pull request #2874 from aanbar/develop

[Cart Library] Allow updating all properties for an item.
[ci skip] Add index.html to system/core/compat/
Merge branch 'develop' of github.com:EllisLab/CodeIgniter into develop
[ci skip] Polish changes from #2874