Unify non-snake-case lints and non-uppercase statics lints

This unifies the `non_snake_case_functions` and `uppercase_variables` lints
into one lint, `non_snake_case`. It also now checks for non-snake-case modules.
This also extends the non-camel-case types lint to check type parameters, and
merges the `non_uppercase_pattern_statics` lint into the
`non_uppercase_statics` lint.

Because the `uppercase_variables` lint is now part of the `non_snake_case`
lint, all non-snake-case variables that start with lowercase characters (such
as `fooBar`) will now trigger the `non_snake_case` lint.

New code should be updated to use the new `non_snake_case` lint instead of the
previous `non_snake_case_functions` and `uppercase_variables` lints. All use of
the `non_uppercase_pattern_statics` should be replaced with the
`non_uppercase_statics` lint. Any code that previously contained non-snake-case
module or variable names should be updated to use snake case names or disable
the `non_snake_case` lint. Any code with non-camel-case type parameters should
be changed to use camel case or disable the `non_camel_case_types` lint.

[breaking-change]

src/libsyntax/ast.rs

@@ -29,7 +29,7 @@ use serialize::{Encodable, Decodable, Encoder, Decoder};
 // FIXME(eddyb) #10676 use Rc<T> in the future.
 pub type P<T> = Gc<T>;
 
-#[allow(non_snake_case_functions)]
+#[allow(non_snake_case)]
 /// Construct a P<T> from a T value.
 pub fn P<T: 'static>(value: T) -> P<T> {
     box(GC) value