Sherpa Prototype

added BLANK line to myprogram.js to help with testing

The model now keeps track of the lines numbers for each statements.
For ASSIGN & BLANK it's just one number stored inside property lines[0].
For IF & LOOP the same property stores the lines numbers of each line used to represent the syntax elements of a given statement, e.g. lines[0] holds the line for the IF, lines[1] the line for the THEN, lines[2] the line for the ELSE, lines[3] the line number for the ENDIF.
This allows to locate the first & last lines of an entire statement in order to add the "SelectedLines" marker to it.
This is done after having a onclick handler go recursively through the statements to mark their selected property to be the opposite of the selected property of the statement we just mouse-downed on

Elementary lines selecting; model / view

Expressions & LValues are validated

First attempt to add a toolkit of buttons to the program view. These will be used later to add / del lines in the sources
still very much draft all this stuff right now

Expressions & lvalues are editables in program
no validation yet
need refactoring to be done pretty soon

Small Steps; preparing to make parts of program's view editables. The renderProgram function is now preparing the view inside a programView variable inside org.sherpa.program.view. This allows to no longer rely on the return values

Just making sure all editables are highlighted in yellow when hovered to make it easier for the user to spot these fields

Adding variables implemented

Redid layout for test so descriptions are before the last.
Added delete button for all variables in the header view
Hooked the buttons to new org.sherpa functions which remove variables from the header & tests models after verifyign the variable is not used in the program's body. Added a tmp variable "even" to myprogram.js so we test removing "even" when "nbeven" is there. need to not try to match sub-words when looking for varname