FIX Not checking stage in SiteTree#canView

SiteTree versions that arent the live version shouldnt be accessed by
regular users, but the logic to check that was split off into canViewStage,
which wasnt checked by code that isnt specifically SiteTree aware
(like RestfulServer)
Merge pull request #792 from hafriedlander/fix/stageaccess

FIX Not checking stage in SiteTree#canView
Fixed installer message escaping, unified usage (fixes #2211)

Same entity was already fixed in a different file,
we can't have them use different strings, so used the new one instead.
Remove PHP 5.5 from allowed failures
Adds LoginForm as an allowed action

Behaves as a form method defined on ContentController
Merge branch '3.0' into 3.1

Conflicts:
	.travis.yml
Updated templates to be more consistent and removed trailing spaces
Edit
Merge pull request #799 from ARNHOE/3.1

Updated templates to be more consistent and removed trailing spaces
Translations: Switch to Transifex format

- Based on new (last) translation download from getlocalization.com
- Removed untranslated strings. Getlocalization started including those at some point
which is highly annoying, unnecessary and breaks the new transfix system,
since it'll mark all of the english strings as actual translations
- Avoid dots in entities. It confuses the Transifex YML parser
- Removed some locales unknown to Transifex which didn't have any translations anyway
- Removed "lolcat" locale, uses custom notation (en@lolcal)
  which SilverStripe's i18n system can't handle
  (needs mapping from SS naming to Zend naming)
- Renamed "Te Reo/Maori" locale from "mi_NZ" to "mi" (Transifex/CLDR notation)
- Namespaced all entities used in templates (deprecated usage)
- Converted dots to underscores where template filenames are used for namespaces,
since Transifex YML parsing handles them as separate YML keys otherwise
- Removed whitespace in entity names, SilverStripe i18n can't handle it
Translations: Switch to Transifex format

- Based on new (last) translation download from getlocalization.com
- Removed untranslated strings. Getlocalization started including those at some point
which is highly annoying, unnecessary and breaks the new transfix system,
since it'll mark all of the english strings as actual translations
- Avoid dots in entities. It confuses the Transifex YML parser
- Removed some locales unknown to Transifex which didn't have any translations anyway
- Removed "lolcat" locale, uses custom notation (en@lolcal)
  which SilverStripe's i18n system can't handle
  (needs mapping from SS naming to Zend naming)
- Renamed "Te Reo/Maori" locale from "mi_NZ" to "mi" (Transifex/CLDR notation)
- Namespaced all entities used in templates (deprecated usage)
- Converted dots to underscores where template filenames are used for namespaces,
since Transifex YML parsing handles them as separate YML keys otherwise
- Removed whitespace in entity names, SilverStripe i18n can't handle it
- Only allow selection of locales registered through i18n::$all_locales to avoid
  issues with unknown locales in Zend's CLDR database
Merge pull request #820 from chillu/pulls/transifex-3.0

Translations: Switch to Transifex format (3.0)
Merge pull request #821 from chillu/pulls/transifex-3.1

Translations: Switch to Transifex format (3.1)
Merge remote-tracking branch 'origin/3.0' into 3.1

Conflicts:
	lang/en.yml
	templates/CMSPageHistoryController_versions.ss
Updated translation master file