Add java.exe as alternate java binary name
Fixed path parsing bug

The ENV_VARS paths were not split and looped, so if a user specified
multiple directories in a single path variable, then they would be
incorrectly processed.

Fix: split the ENV_VAR on os.pathsep, loop it and then os.path.join() it
with the filename to create the possible file location.
Updated internals.py to make find_file consistant

find_file now consistently searches for the bin name and the alternative file_names
Fix collocations.doctest. See #399
more precise docstrings for FreqDist.keys, FreqDist.values and FreqDist.samples. Fixes #390.
Remove conditional imports from nltk.classify.__init__. This fixes #368.
Remove conditional imports in nltk.tag and nltk.tokenize. See #368.
Merge pull request #412 from kmike/no-conditional-imports

Remove unnecessary conditional imports
Restoring backwards-compatibility

Based on comments from @kmike

Also added extra comments for clarity
Removed incorrect comment, corrected verbose print statement, and
removed unnecessary line
Restored backwards compatibility to find_file
Merge pull request #409 from dougalg/master

Added java.exe as alternate binary name for Java