new parser that uses flex and bison

new parser that uses flex and bison

Original commit message from CVS:
* new parser that uses flex and bison
- doesn't do dynamic pipelines yet...
* added GErrors to the gst_parse_launch[v] api
* added --gst-mask-help command line option
* fixed -o option for gst-launch
* GstElement api change:
- gst_element_get_pad
- gst_element_get_request_pad, gst_element_get_static_pad
- gst_element_get_compatible_pad
- gst_element_get_compatible_static_pad, gst_element_get_compatible_request_pad
- gst_element_[dis]connect -> gst_element_[dis]connect_pads
- gst_element_[dis]connect_elements -> gst_element_[dis]connect
* manual update
* example, tool, and doc updates for the api changes
- no more plugin docs in the core docs, plugins require a more
extensive doc system