fix inconsistent capitalization of sign-up/sign-in links

* merged latest upstream master
* made consistent capitalization of all Sign-Up and Sign-in links
* added links:sign_up: translation placeholders for all languages (need translations)
* added general:or: transations for all languages
* all oauth providers are listed in Home#index 'Contribute' section
* added ApplicationHelper#list_friendly_text method for the previous feature
add cross-dev Gemfile

* added cross-dev Gemfile
* fixed some typos
* updated dev wiki link in README.md
* updated 'bootstrap_form' gem in Gemfile

the 'sigmike/bootstrap_form' gem added to the Gemfile in
      https://github.com/tip4commit/tip4commit/pull/74
  has been merged upstream
      https://github.com/bootstrap-ruby/rails-bootstrap-forms/pull/76
  it was added apparently as a bugfix but is now quite outdated
  it was upgraded in the peer4commit repo in june
      https://github.com/sigmike/peer4commit/commit/
              608980f7bd7b9fde5366180142f050d7baaf27a1
Add titanous/* and flynn/* to blacklist
Blacklist mbabker/*, BabDev/*/ and joomla*
Fixes to Russian spelling.
merge latest upstream master
Merge pull request #176 from titanous/patch-1

Add titanous/* and flynn/* to blacklist
Merge branch 'patch-1' of github.com:mbabker/tip4commit into mbabker-patch-1

Conflicts:
	config/blacklist.yml
Merge branch 'mbabker-patch-1'
Merge pull request #179 from crayxt/patch-1

Fixes to Russian spelling.
Merge branch 'sign-up-links' of github.com:bits4commits/bits4commits into bits4commits-sign-up-links

Conflicts:
	config/locales/ru.yml
Merge branch 'bits4commits-sign-up-links'
fixing #180
fixing #175
Blacklist my personal (mpasternacki) and my organization's (3ofcoins) repos
fixed polish translation
Merge pull request #181 from mpasternacki/master

Blacklist my personal (mpasternacki) and my organization's (3ofcoins) repos
fixing #182; also added some text to warning to prevent further confusion
Merge pull request #183 from nalesnikld/master

fixed polish translation
Merge pull request #144 from bits4commits/dev-tweaks

add cross-dev Gemfile and update 'bootstrap_form' gem