Start implement lvalue check in IL instruction.

Add lvalue check on fb invocation.

Literals are also part of expressions!

Implement check_assignment_to_expression in lvalue_check_c class.

Remove potential access to NULL pointer.

Start having nicer stage 4 error messages.

Improve usability command line under windows.

Ignore trailing EOLs when determining symbol location.
(Makes for niver error messages)

Add comment.

Fix Segmentation fault in check_assignment_to_output lvalue method.

Remove deprecated status for ANYTIME operations.

Produce similar error messages in stage2 and stage3.

Fix bug when handling code with data type errors.

Fix printing of data type errors in while and repeat statements.

Add lvalue check for non formal function invocations.

Fixing check for assingment to FOR control variables.

Moving get_var_name_c into its own file.

Fixing check for assignment to output variables.

Fixing some bugs in lvalue checking (other bugs remain - to be fixed later)

Add lvalue check class.

Determine the modifiers (CONST, REATAIN) used when declaring a variable.

Fix typo in comparison expression.

Removing code from search_varfb_instance_type_c (use search_var_instance_decl_c instead).
(Preparing to delete search_varfb_instance_type_c in the future!)

Fix bug by expanding permissible data input of search_var_instance_decl_c
(this will also prepare us for removing search_varfb_instance_type_c in the future)

Edit formating and delete unused code.

Start data type checking of var declarations (including direct variables!)

Delete incorrect comments I had inserted previously (confusing EQ and NE functions)

merging with Lauren't changeset.