enumerate(x) documentation update

Added example and added "plain english" explanation of when the function is useful
fix #6808 and #6854

when tests are run on a single core, the RNG ends up with sprb45 having 16 nonzeros
Fix edit() when editor is Sublime with arguments

Example: EDITOR="sublime --wait"
Minor revisions on LinAlg docs 

Formated a few examples, added some returned values, etc
Merge pull request #6862 from brk00/patch-2

enumerate(x) documentation update
Merge pull request #6865 from jayschwa/fix-sublime-with-args

Fix edit() when editor is Sublime with arguments
Merge pull request #6867 from brk00/patch-4

Minor revisions on LinAlg docs
Merge pull request #6863 from tkelman/patch-4

fix #6808 and #6854
doc spelling: witch => which
Merge branch 'master' of github.com:JuliaLang/julia
Added introduction to variables to the manual

Simple explanation about variables
Fixed typo
Changed examples comments

Formated the comments to match the rest of the manual
Corrected returned value
Only purge sys.$(SHLIB_EXT) if JULIA_CPU_TARGET == native
Merge pull request #6875 from brk00/patch-6

Added introduction to variables to the manual
Update for LLVM35 changes
Makefile: DEBUG -> JL_DEBUG_BUILD to avoid LLVM conflict
Add code_native support for MCJIT
Add partial support for line info.

Use ';' as separator in LLVM function name, and add jl_demangle