Remove Distribution.Client.Compat.Exception

Since GHC 6.12.3 is no longer supported, it's no longer necessary.
Doc patch: provide a pointer to where the list of --with-PROG values is.  Fixes #1512.
GHC-7.6+ on ARM does support -threaded

Thanks to Austin Seipp <austin@well-typed.com>
Add a quickstart to the development chapter of the user guide

It covers using cabal init and the basic steps for building from there.
Rewrite and extend several parts of the user guide introduction

Introduce cabal-install much earlier. Give more of a basic intro.
Try using a contents within each user guide chapter

Currently we have a somewhat hard-to-maintain contents just in the
introduction. This cuts that initial contents down to just link to
the chapters (plus sections within the intro), and then use an
automatically generated table of contents in the other chapters.

Also tweak the CSS because pandoc's TOC feature turns all section
headings into links and that changes the visual appearance. Use the
CSS to make it look the same as before.
Limit the length of lines in the user guide html to be readable
Add a user guide section on package concepts
Merge pull request #1508 from benmachine/nocompat

Remove Distribution.Client.Compat.Exception
Fix Makefile on OS X

tar on OS X didn't like

    tar -c file -zf file.tar.gz

but does accept

    tar -czf file.tar.gz file

Also added an option to use a different SSH user.
make release also uploads to Hackage
Revert "make release also uploads to Hackage"

Since we use the same script for release candidate, which we don't want
to upload to Hackage, remove the automatic upload to Hackage.

The user of make release is supposed to manually run

    cabal upload $(DISTLOC)

after make finishes.

This reverts commit c798644aded3308764a5f1dd19805703b3ebb488.
Fix a mistake in the user guide section order
Add -L flag to `curl` usage in cabal-install/bootstrap.sh for redirects
Merge pull request #1521 from mkscrg/master

Fix `cabal-install/bootstrap.sh` for the new Hackage server
Suggest that 'ExitFailure 9' is probably due to memory exhaustion.

Fixes #1522.
Add a key-value map to the Compiler type.
Use the compilerProperties map instead of invoking 'ghc --info'.

Fixes #1442.
Fix cabal repl handling of Ctrl-C
Merge pull request #1523 from 23Skidoo/exit-failure-9

Suggest that 'ExitFailure 9' is probably due to memory exhaustion.