added history draft document
added HistoryButton and HistoryWidget
discarded previous implementation of history
connected datastore init to history widgets
applied common prefixes to HistoryWidget class:

i -> incomming public interface
sig -> outgoing signals
_ -> private/protected methods
changed i prefix to slot
more name changes
more renaming
normalized file browser naming
adjusted naming of the remaining files
made c++11 flags more portable
more project file clarity tweakes

- note: we are targeting Qt5/C++11 as minimum
made headers more consistent
moved button and widget class sources into subdirectories

makes the project files more explorable
fixed bug for loading DsTableFav tables

refactored error reporting from bool return values to assertions
moved DsTable* initTable -> constructor
moved headers, presetwidget