start of adding hash_key
notes
still need to update sparse
finishing up hash_key
fixed bug found in testing
Merge branch 'master' into hash_key
updated build_test script to remove ree
version number
add failing test case for hash_key returning a Symbol

- results in "can't modify frozen Symbol"
Merge pull request #180 from dchelimsky/test-case-for-hash-key-returning-symbol

add failing test case for hash_key returning a Symbol
fixed new test and problem with hash_key and non-string keys
changed 1.0 to 1.0L to force double type
release 2.10.0