Add a warning for unbound constraints in the validating loader

Closes #2165
Added a new FAQ entry about unbound version constraints
Ignore ambiguous classes in tests/fixtures dirs, fixes #2858
Fix classmap generator warnings and tests
update homebrew instructions
forget a homebrew step that's required for php installation
use php 5.5 in homebrew instructions
Fix typo
Merge pull request #2870 from pierredup/patch-1

Fix typo
Merge pull request #2868 from zeke/master

update homebrew instructions
Only print suggestions in dev mode

There is no need to clutter the screen/logs/whatever with suggestions in production installs. If someone didn't care about them in dev mode, they certainly won't in production :)
Merge pull request #2883 from dzuelke/dev-suggestions

Only print suggestions in dev mode
Fix boolean check fail from a8ec134c2c34482bedf08c6d022cbbc5ca3fa7bc
Process remove ops first, fixes #2874
Fix integration tests
fixed: dead symlink breaks gc
Merge pull request #2888 from BreiteSeite/master

fixed: dead symlink breaks gc
Clarify log messages when skipping existing bins
Merge pull request #2891 from igorw/skip-bin-log-msg

Clarify log messages when skipping existing bins
Merge remote-tracking branch 'stof/doc_unbound'