remove php 5.3 from Travis build matrix
add InstanceCreationDisallowerTrait
update badges
Merge pull request #6 from keradus/badges

update badges
Merge pull request #2 from keradus/InstanceCreationDisallowerTrait

add InstanceCreationDisallowerTrait
update composer branch-alias
add InnerClassCacheTrait
Merge pull request #5 from keradus/InnerClassCacheTrait

add InnerClassCacheTrait
add SingletonTrait