Renamed Repository from BasicPlugin

Renamed package BasicPlugin to Core
Renamed class BasicPlugin to PluginCore
Update README.md
Fixed Nullable
Merge branch 'dev' of https://github.com/eli112358/PluginCore into dev
Added @Nullable tags

to getSecondaryPriorities()
and getPrimaryPriority()
Renamed iml file
Rearranged code

and added craftbukkit to classpath
Fixed many issues  with new Schedule system

Added PriorityConflictException
Added configurable debugging
Rearranged a lot of code
Fixxed more bugs in add on system
Removed add-on system

Priorities are now in Resources
Priority Resources are fully functional

Also rearranged some code
Merge pull request #1 from eli112358/dev

Dev