Changed the object-in-hand goal so that it retries grasping several times

Instead of re-perceiving the object to grasp instantly when grasping didn't work, try to grasp it from another angle again. This happens three times before it is re-perceived. This way, the PR2 gets more chances to actually get the object into it's gripper(s) without instantly moving far away to get a better view.

Also, the location described as `(to execute)' the grasp actions is replaced by the `(to reach)' description. This expresses the intent of the location very clearly.
Added some demo related changes
Added `a' and `and' macros for more readable (and quicker) designator creation
Package exports for the `a' and `an' designator macros
Changed the `json' to `yason' tag for compatibility reasons with groovy
Changed header include file names to new versions in groovy (for assimp lib)
Removed commented code
Exported symbols 'feature-constraint and 'geometric-feature, necessary to use the classes.
Added initform to internal feature and constraint representations, where useful.
Added convenience functions to create point, line and plane features.
Added type declarations to convenience functions.
Removed empty file 'cram-feature-constraints.lisp'
Got rid off unnecessary TODO.
Removed never-used function.
Added sane default values for some of the aux-functions.
Added and exported further auxiliary functions to create constraints.
Exported symbol of new goal for a plan: object-flipped.
Extended method 'designator-solutions-equal': If transformation into common frame *fixed-frame* is not possible, a comparison in common frame in *robot-fixed-frame* is tried before faulting with nil.
Revert "Changed header include file names to new versions in groovy (for assimp lib)"

This reverts commit 01a31046ed7d2e4ee1c99c4ff4cb22a99e2ff1ab.
Added auto-patching within the cmake-process for assimp-grovel.lisp

Between 12.04 and 12.10 there was a breaking change with respect to libassimp include header filenames (in /usr/include/assimp). The herein introduced CMakeLists.txt file (and accompanying patch file in the src/patches folder) take care of setting the correct files to grovel for.