Changes:
 - do not use "?timestamp" in HTML, because of better browser caching
 - rewrite LessFilter for less.php (git://github.com/Mordred/less.php.git - it compiles LESS v1.3.0)
 - added debug panel for webloader
 - BOMFilter removes BOM from UTF files
 - CssCharsetFilter write only one "@charset 'utf-8'" at the beginning of the generated file
 - CoffeeFilter compile .coffee files using coffeescript/coffeescript
FileCollection:
 - add searched suffixes if added file does not exist
Added is_file() test to FileCollection and copy suffixes in render() function in Nette\WebLoader
FIX warning in Compiler::generate()
Add dependend files cache to the compiler. This will allow regeneration of the file if its dependency change mtime. Also added parsing "@import" to the LessFilter. E.g. If we have "bootstrap.less" which has content '@import "variables.less"', the "bootstrap.less" will be also regenerated if the "variables.less" has been changed.
Add to FileCollection::addFile parameter $need. If $need == TRUE an exception will be thrown if file does not exist.
Allow to set root folder and add fallback folders.
E.g.:
  You have a theme system. You can add global directory as fallback folder.
  Then if theme file does not exist, WebLoader will take file from global directory.
Added better parsing of @import ""; in LESS files
Custom realpath implementation, which cannoncalize path,
because PHP realpath return FALSE if "custom" directory
does not exist in path "/tmp/custom/../own.css"
Skip files from .dependencies if the file doesn't exist.
Diagnotics: Removing <strong> from name of the panel
FIX: FileCollection::realpath() if $path starts with '..'
Make CSS @charset REGEXP case insensitive
Normalize 'charset' only if there is at least one at the code.
Added LocalCssFilesFilter for copying files relative to the source
file to output directory so the url(..) references are not broken
Added LinkFilter for parsing {{link ...}} macros which will be replaced by URI (like {plink} in Latte)
Use git://github.com/leafo/lessphp.git for LessFilter
Make LinkFilter regexp not greedy
Allow prepend files to the FileCollection
Allow absolute path in LESS @import-s