Use ConcurrentLinkedHashMap for layer cache to allow for LRU aging and
eviction of stale cache entries.
Merge pull request #3 from chuckdumont/master

ConcurrentLinkedHashMap for layer cache
Customization feature fails on Windows server
Merge pull request #4 from chuckdumont/master

Customization feature fails on Windows
Fix for Dojo 1.8 (calling has for some features throws exception if
called too soon).
Merge pull request #5 from chuckdumont/master

Fixe for dojo 1.8