Composer package config created

Converted to cakephp-plugin package.
Readme changed

Added a composer installation method
Whitespace fix
Minimum stabilitye added
Composer changes
Update readme.md
Changed logic of key-value forming

Such method allows to choose diferent keys for values
Validation fixed
Some comments fix
Readme changes
Merge pull request #4 from a-bashtannik/master

Merged `a-bashtannik`'s [https://github.com/a-bashtannik] pull request to make this plugin `Composer` compatible.