Fix LookupError for unknown encodings.

Sets the preferred encoding to UTF-8 if python is unable to find a codec
for the value returned by locale.getpreferedencodings() function.
Update contribManager list with recent contrib scripts
Merge PR #960
Update travis configuration to pull correct minecraft JAR

MC_VERSION will need to be adjusted as part of each update
More agressive texture cache

Especially with regard to jarfile loading
Merge PR #967
Add note about distutils bug.
more better fix for HOME being set on windows
Merge pull request #970 from CounterPillow/patch-1

Add note about distutils bug.
Added more explicit example for texture pack downloading
Updated the wording in the texture installing docs to be less confusing
missed the quotation block
updated texture version to 1.6.2
more wording adjustments
fixed --check-terrain with --config
findGitVersion() ignores non-versiony tags
fixed new version incantation to work on windows
fixed hiding JSObserver info box when unused
Added clarification on 'northdirection' that it has to do with viewpoint angle
Fixed the way texture.py searched for foliage, grass and chests textures.
This is a "quick-and-dirty fix", you may improve it as I'm novice in Python.
Default files in data/textures have been renamed to reflect changes in new 1.6 texture packs (aka resource packs)