General fixes for vim

Makes colorcolumn setlocal instead of set.
Makes conceal opt-in.
Removes the seem-to-be obsolete old keywords/types

src/etc/vim/after/ftplugin/rust.vim

@@ -1,5 +1,5 @@
 "Highlight the 100th text column
 "Feature became available in v7.3
 if version >= 703
-    set colorcolumn=100
+    setlocal colorcolumn=100
 endif

src/etc/vim/after/syntax/rust.vim

@@ -1,4 +1,4 @@
-if exists('g:no_rust_conceal') || !has('conceal') || &enc != 'utf-8'
+if !exists('g:rust_conceal') || !has('conceal') || &enc != 'utf-8'
 	finish
 endif
 

src/etc/vim/syntax/rust.vim

@@ -29,7 +29,7 @@ syn match     rustIdentifier  contains=rustIdentifierPrime "\%([^[:cntrl:][:spac
 syn match     rustFuncName    "\%([^[:cntrl:][:space:][:punct:][:digit:]]\|_\)\%([^[:cntrl:][:punct:][:space:]]\|_\)*" display contained
 
 " Reserved words
-syn keyword   rustKeyword     m32 m64 m128 f80 f16 f128 be
+"syn keyword   rustKeyword     m32 m64 m128 f80 f16 f128 be " These are obsolete
 
 syn keyword   rustType        int uint float char bool u8 u16 u32 u64 f32
 syn keyword   rustType        f64 i8 i16 i32 i64 str Self