Fix Pcbnew block rotate hot key and minor code cleaning.
Pcbnew: Fix issue when displaying net names and/or pad numbers including the "<" char in drc dialog, because drc dialog uses an wxHtmlWindow to display drc messages, and the "<" char has a special meaning and is not allowed in texts (now replaced by the" &lt;" sequence in messages displayed in html)
Eeschema: replace "<" and ">" by "(" and ")" in autogenerated net names, to avoid other issues in html messages.
Very minor other fixes.
Planning for PCB_BASE_FRAME::Save_Module_In_Library and PCB_EDIT_FRAME::ArchiveModulesOnBoard rewrites