Preliminary support for a :let command in the repl
Changed :let to work with an arbitrary number of `PDecl`s (though only one name at a time for now).

	It is no longer possible to leave off the type declaration. This will be fixed soon.
Create the CaseBuilder monad alias.
Add ReaderT to CaseBuilder.
Add getInaccessibleArgs.
Bring erasure info to the case tree builder.
Added some additional documentation for partial evaluation
Handling more forms of definition.

	 In particular, it should now be possible to define multiple names at once, and to
	 leave off type declarations when the type can be inferred.
Removed some commented-out code
Added support for data definitions
Extend argsToAlt to return a quadruple.
Adjust code around argsToAlt.
More changes to argsToAlt.
Implement accessible+inaccessible splitting.
Disable PAny for repeated patvars.
Purify toPats.
Comment clarification.
Simplify argsToAlt.
Merge pull request #1358 from ahmadsalim/documentation/partialevaluation

Added some additional documentation for partial evaluation
Merge pull request #1360 from ziman/case-elab-erasure

Make case elaboration respect dots