Default mappings and better form selection

• The mappings that were mentioned in the README are now included by default, you can opt out with let g:conjure_default_mappings = 0.
• ConjureEvalCurrentForm and ConjureEvalRootForm now take [] and {} pairs into account.
• Merged #3 which cleaned up some JVM arguments.
• Lots of code shuffling into autoload/lua files.