Add default return value for request data

Allow overloading of the default return value of NULL when
requesting request data.

Example:
  http://host/action?foo=bar&abc=123

  $app->request->get('foo')        -- [bar]
  $app->request->get('bar')        -- [NULL]
  $app->request->get('bar', false) -- [FALSE]
Fix Environment path parsing regression
Merge branch 'release-2.3.4'
Bump version number
Fix urlFor adding extra slashes on Windows OS #663
Merge branch 'release-2.3.5'
Bump version
Changed from ltrim to str_replace to remove multiple backslashes
Add (string) case in encodeSecureCookie call to hash_hmac

Per http://php.net/manual/en/function.hash-hmac.php, the second argument to hash_hmac is supposed to be a string. HHVM (http://www.hhvm.com) is more strict about checking the arguments.
.travis.yml - add PHP 5.5
Add property typehints for proper IDE support.
Fix ordering
Don't rely on system setting for error_reporting level
add 418 HTTP status code

See RFC 2324
https://tools.ietf.org/html/rfc2324
Remove redundant call to setTemplatesDirector method.
Pass through 'templates.path' to view object singleton.
Allow local data to be passed into a template during rendering.
Merge remote-tracking branch 'dongilbert/IDE' into release-2.3.6
Merge remote-tracking branch 'sasezaki/patch-1' into release-2.3.6
Merge remote-tracking branch 'chrisgedrim/master' into release-2.4.0