Use GAMS builtin `execError` for counting execution errors and stop looping

Removed now obsolete scalar `errorcount`.

Solves #102

Backbone.gms

@@ -128,7 +128,7 @@ $include '%input_dir%/modelsInit.gms'
 
 * === Simulation ==============================================================
 $include 'inc/3a_periodicInit.gms'  // Initialize modelling loop
-loop(modelSolves(mSolve, tSolve),
+loop(modelSolves(mSolve, tSolve)$(execError = 0),
     solveCount = solveCount + 1;
     $$include 'inc/3b_periodicLoop.gms'         // Update modelling loop
     $$include 'inc/3c_inputsLoop.gms'           // Read input data that is updated within the loop
@@ -167,5 +167,5 @@ execute_unload '%output_dir%/results.gdx',
 $ife %debug%>0
 execute_unload '%output_dir%/debug.gdx';
 
-if(errorcount > 0, abort errorcount);
+if(execError, abort execError);
 * === THE END =================================================================

CHANGELOG.md

@@ -11,6 +11,7 @@ All notable changes to this project will be documented in this file.
 
 ### Changed 
 - Updated tool defintions for Sceleton Titan and Spine Toolbox
+- The program will now stop looping in case of execution errors.
 
 ### Fixed
 - Removed hard-coded `elec grids` from *setVariableLimits* and *rampSched files*

inc/1c_parameters.gms

@@ -17,7 +17,6 @@ $offtext
 
 * --- Internal counters -------------------------------------------------------
 Scalars
-    errorcount /0/
     solveCount /0/
     tSolveFirst "counter (ord) for the first t in the solve"
     tSolveLast "counter for the last t in the solve"

inc/4c_outputQuickFile.gms

@@ -31,7 +31,7 @@ set metadata(*) /
    'GAMS system' '%system.gstring%'
 $include 'version'
 /;
-if(errorcount > 0, metadata('FAILED') = yes);
+if(execError > 0, metadata('FAILED') = yes);
 
 put f_info
 put ""/;