Implement functionality to replace tabs with spaces and vice-versa.
On branch master, changes to be committed:
	modified:   src/mainwindow.cpp
	modified:   src/mainwindow.h
	modified:   src/mainwindow.ui
	modified:   src/scintillaeditor.cpp
	modified:   src/scintillaeditor.h
Add files that define Find/Replace dialog.

On branch master, changes to be committed:
	modified:   src/Lepton.pro
	new file:   src/findreplacedialog.cpp
	new file:   src/findreplacedialog.h
	new file:   src/findreplacedialog.ui
Define basic GUI for find/replace dialog.
On branch master, changes to be committed:
	modified:   src/findreplacedialog.ui
Implement find/replace functionality.
On branch master, changes to be committed:
	modified:   src/findreplacedialog.cpp
	modified:   src/findreplacedialog.h
	modified:   src/findreplacedialog.ui
	modified:   src/mainwindow.cpp
	modified:   src/mainwindow.h
	modified:   src/mainwindow.ui