added interface ILogger

Conflicts:
	src/Tracy/FireLogger.php
Debugger::$source replaced with Helpers::getSource()

Conflicts:
	src/Tracy/Debugger.php
	src/Tracy/Helpers.php
	src/Tracy/templates/bluescreen.phtml

Conflicts:
	src/Tracy/Debugger.php
Helpers::createHtml renamed to formatHtml (BC break)

Conflicts:
	src/Tracy/Dumper.php
Debugger::log() whole logic from moved to Logger (BC break)

Conflicts:
	src/Tracy/Debugger.php
	src/Tracy/Logger.php
	tests/Tracy/Debugger.log().phpt

Conflicts:
	src/Tracy/Debugger.php
	src/Tracy/Logger.php
	tests/Tracy/Debugger.log().phpt
Debugger: removed deprecated $mailer and $emailSnooze, use variables in $logger (BC break)
Define severity for logging whole bluescreen in production mode [Closes #56]

Conflicts:
	tests/Tracy/Debugger.logSeverity.E_NOTICE.phpt
Debugger: $logSeverity is ignored in development mode
Bluescreen: some logic moved from template to render()

Conflicts:
	src/Tracy/templates/bluescreen.phtml
Some fixes