New validators for input type file. Useful when multiple attribute enable.

New options:
- maxFiles: The maximum number of files
- minFiles: The minimum number of files
- maxTotalSize: The maximum size in bytes for all files
- minTotalSize: The minimum size in bytes for all files
Merge branch 'master' of https://github.com/morrizon/bootstrapvalidator into morrizon-master

Conflicts:
	dist/css/bootstrapValidator.min.css
	dist/js/bootstrapValidator.js
	dist/js/bootstrapValidator.min.js
Merge branch 'morrizon-master'
#1001: Add minFiles, maxFiles, minTotalSize, maxTotalSize options for the file validator, thanks to @morrizon