Added TODOs from IdeSlave.hs
Add syntax for example code to docs

Now, code defined with the "example" Markdown attribute will be rendered
as an inline REPL-style example. For instance:

````idris example
with List (reverse ["a", "b", "c"])
````

renders to

        > reverse ["a", "b", "c"]
        ["c", "b", "a"]
Lifted TODOs and FIXMEs from clause and instance elaborator
Removed old comment from `src/Idris/Elab/Data.hs`
Added TODOs and FIXMEs from the Elaborator for Data.
Lifted the TODOs from Primitives.hs
Merge pull request #1613 from david-christiansen/doc-examples

Add syntax for example code to docs
Removed '_|_' as a built in declaration and renamed it to 'Void',
'FalseElim' now 'VoidElim' to match up
Renamed VoidElim to void in order to ensure further consistency
Factor `addSyntax` out of `syntaxDecl` parser
:let at the REPL now supports syntax extensions!
Merge branch 'master' of https://github.com/idris-lang/Idris-dev into repl-definitions
Solve more implicits before 'case' elaboration

Otherwise we can generate a type for the 'case' block which is not
specific enough, if there are lots of dependencies. Fixes #1620.
Merge branch 'master' of git://github.com/idris-lang/Idris-dev into case-fix
Merge pull request #1618 from jfdm/tidyup/lift-todos-3

More lifting of TODO/FIXMEs from the source.
Merge pull request #1621 from trillioneyes/repl-definitions

Repl definitions
Merge pull request #1622 from edwinb/case-fix

Case fix
Fix for pattern vars in transforms

We'll need this when making rewrite rules for partially evaluating type
class dictionaries.
Partial evaluator fixes

Need to identify when a specialisation has made no progress, so we don't
treat it as a specialisable application. Also fixes tranform rules.

With this it turns out to be safe (if not yet useful) to mark type class
dictionaries as 'static', but without further work on the partial
evaluator this isn't going to help much yet, so it's not enabled yet.
Merge pull request #1623 from edwinb/patvars

Fix for pattern vars in transforms