Improvements in WPS interface

*Improvements include:
*Multiple values are now allowed for literals (entered as comma separated values) and Enums (selected from a list), when maxOccur > 1
*Boolean fields are dropdown box instead of empty text boxes
*added validation for
  - GML/WKT/JSON
  - Literal values check for min-max
  - Numeric values check for valid strings
  - URLs in references
*Default values are shown when available
*After editing a subprocess, if the edit link is used, the subprocess dialog already contains the values entered previously
*When defining a subprocess only those processes that generate the type of output needed to feed the parent process are available
*CRS panel is displayed in a IFrame when part of a subprocess, avoiding problems when closing the CRS panel itself
*Checking for mandatory parameters has been added in some types of inputs where it was missing.
*A few additional minor fixes