Base documentation - minor revisions

Many revisions on the base.rst. Formated and added new examples, inserted some returned types, etc.
Corrections on base.rst previous commit

Removed type annotation of some functions
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
MCJIT code_native fixes

Support LLVM trunk
Full backtrace line info
Fix disassembly line numbers
Properly initialize some variables.
Clean up merge cruft and make ';' mangling MCJIT-only
Use FunctionNameKind::ShortName, thanks to upstream making this available
Merge pull request #6737 from ihnorton/mcjit_disasm

MCJIT code_native support
sizehint for Sets now returns the given Set

It previously returned the Dict as-per:

    https://groups.google.com/forum/#!topic/julia-users/COdDQwrgKQQ
Consistent formatting as per feedback from @ivarne
Merge pull request #6883 from ninjin/nin/set_sizehint

sizehint for Sets now returns the given Set
Fix multimedia display in REPL code
Corrected identation and comments
initializing default id to 1
Merge pull request #6889 from amitmurthy/amitm/id

initializing default id to 1
use size in hashing AbstractArrays

make hashing test stricter to also check for collisions. there shouldn't be
any for these simple cases.
Merge branch 'master' of github.com:JuliaLang/julia
Typo.

I must be the first person to use this generic :-)
Merge pull request #6890 from JuliaLang/db/syr

Correct a typo in BLAS.syr!
fix missing argument in print_help_entries
Fix typo in BLAS level 3 perf tests and make tiny large enough to call BLAS