Multiple fixes for JSON and eeb server environment support

- Fixed bug in Apache module where errors were handled improperly and blank data was sent to user
- Added error message pragma #HTTP_ERROR which ends the program, logs it, and prints a default error message to the user
- Remove malplaced semicolon which the  CONTENT_TYPE-pragma put in the HTTP header
- Fix error message output in wpl_element_exception, print the whole line the error is on
- Support run time resolving of SCENE name in SCENE pragma and expression support with @-prefix
- Enable set_weak in POST value so that it can be passed as function argument, using shared_ptr on all values.
- Fix recognition of application/x-www-form-urlencoded