* auto-save was broken for all sub sheets with are in a sub-directory of the project directory. (reason wxFileName::Normalize(), used to create the absolute path has issues with filenames starting by '$', perhaps due to env var which also start by $). the auto-save prefix is modified ( now AUTOSAVE_PREFIX_FILENAME which defines "_save_" ) and defined only once.
* auto-save files from sub-sheets were not found due to the fact the path was not set (fixed by Blair Bonnet's patch)
* Use only double to store zoom levels in class BASE_SCREEN (int type is not working for eeschema or page layout editor) (this fix Bug #1450551, Assertion failed on wxRound() when zooming)
* Fix crash in all apps but Pcbnew when a grid or a zoom was selected from the popup menu.
* Modify default hotkeys for Next Grid and Previous Grid: the initial key was a dead key, not suitable as hotkey. the 'N' and Shift N keys are used instead (with a change for unfill zone hotkey)
* Modify code in EDA_DRAW_FRAME::SetNextGrid() and EDA_DRAW_FRAME::SetPreviousGrid() to make them compatible with other editors than the board editor.
* Add code to test if any of the components in the schematic cache have been changed
in the component libraries.
* Prompt user to accept or reject components when changes are found.
* If the user chooses to use the components in the cache, create a new library with the old
components and add it to the beginning of the component library list so the schematic will
not be changed.
* Create dialogs to handle user feedback and status.
Previously, only the lib named "power" was used (and therefore power parts defined in other libs not shown).
Now, all power parts can be loaded from any library.
Also, when loading power parts from the chose component dialog or the lib viewer, libs and parts are filtered: only power parts and libs containing power parts are listed.
Hotkeys: move a few global strings in the files where ther are actually used (and make them local.) and code cleaning.
Fix a few other minor issues.
* Remove redundant definition of KICAD_DATA_PATH since DEFAULT_INSTALL_PATH
was already defined.
* Use DEFAULT_INSTALL_PATH as the substitution for the default environment
variable paths.
* Add option to define DEFAULT_INSTALL_PATH during CMake configuration with
fall back to CMAKE_INSTALL_PREFIX if not not defined.
* Developer note: this change is primarily for package builders where
CMAKE_INSTALL_PATH is the path where the package builder temporarily
installs the build output before creating the package. When building
packages, DEFAULT_INSTALL_PATH should be set to the path where the
package will be installed by default.