[CHANGE] Add support for curl proxy settings configured in the TYPO3 install tool

Use the curl configuration from system configuration. For TYPO3 4.5-LTS
to 6.1 use settings from $TYPO3_CONF_VARS[SYS][curl*]. Starting with
TYPO3 6.2-LTS use $TYPO3_CONF_VARS[HTTP] settings.
[CHANGE] Update documentation and information for hipChatCurlVerifySsl option
[CHANGE] Update icon files and screenshot to reflect new HipChat logo
Merge pull request #1 in MWT3EXT/hipchat from feature/v1.1.2-Curl-Proxy-Settings to develop

* commit 'd8aaed0bebe27b31dec8505d12ef2b7e19ac2737':
  [CHANGE] Update icon files and screenshot to reflect new HipChat logo
  [CHANGE] Update documentation and information for hipChatCurlVerifySsl option
  [CHANGE] Add support for curl proxy settings configured in the TYPO3 install tool