Eeschema: bug fix: after a "De Morgan" convert command, the component was left selected (.m_Flags not cleared)

* Create library collector class.
* Add clarification menu to library editor when multiple items are found
  at the current position.
* Add get clarification menu text to all objects derived from LIB_ITEM.
* Add get menu bitmap for all objects derived from LIB_ITEM.
* Improve LIB_PIN bounding box calculation.
* Rename LIB_ITEM::DoGenCopy to doClone to match behavior defined in base
  class EDA_ITEM.
* Minor class renaming for improved code consistency.
* Added less than operator to EDA_ITEM.

2) switch spec format to *.fodt, and edit it, mentioning lots of defaults.

3) Code pin_merge, but did not test it.

Coding policy fixes and dialog design rules cosmetic enhancement.

gr_basic.cpp: fix a bug I created in my last commit. Pcbnew: fix a very minor bug in hight light behavior

gr_basic: fix incorrect clipping of thick lines (due to changes in code, the thickness was not taken in account to calculate the clip box size)
Pcbnew: fix a very minor bug.

gr_basic: fix incorrect clipping of thick lines (due to changes in code, the thickness was not taken in account to calculate the clip box size)

Made symbol text capable of overlining. Format for text is slightly changed: now text with quotes and/or tildes saved in quoted format: it will cause libraries to fail loading in older versions when ~s or "s are used in text.