Example of pre-configured locale key

Added example of pre-configured locale key to be set en app.php in order to avoid repeat it in every translatable model
Locale key pre-configured

Adding possibility to pre-configure locale key. This way don't have to be redefined in every model that use translation.
Added dependencies for laravel 5 (develop)
Enabled creating fallback translations dimsav/laravel-translatable#52
Cleaned up
Fixed test migrations for laravel 5.
Merge branch 'master' into laravel-5
Removed tests' compatibility with laravel 4.
Merge pull request #60 from lan0/fallback-translations

Enabled creating fallback translations dimsav/laravel-translatable#52
Merge branch 'development' into laravel-5

Conflicts:
	Translatable/Translatable.php
Fixed variable names.
Merge pull request #47 from plmarcelo/development

Pre-configure the localeKey name
Updated readme.
Added tests for the locale-key-per-model configuration.
Moved the package classes under the src directory.
Created package config file.
Renamed configuration key.
Renamed configuration key.
Added config description.
Updated readme for version 5.