surround opening files with try/catch; separate writing files to dedicated writer class, access values via inputdata interfaces

Merge pull request #270 in VECTO/vecto-sim from ~EMQUARIMA/vecto-sim:feature/VECTO-349-extend-gui-for-multiple-steered to develop

* commit '64f89fda':
  vecto gui: add multiple steered axles, reading/writing of multiple axles; validation of auxiliaries
  remove no-longer required methods

Merge pull request #269 in VECTO/vecto-sim from ~EMQUARIMA/vecto-sim:feature/VECTO-345-case-insensitive-parsing-of-csv to develop

* commit 'c2003475':
  make cycle reader case insensitive
  extend testcases for case-insensitiv cycle detection/reading
  refactoring cycle tests, refactoring cycle reader
  test case sensitivity of datatable columns

Merge pull request #268 in VECTO/vecto-sim from ~EMQUARIMA/vecto-sim:feature/VECTO-348-separate-columns-e_gbx_axl-into to develop

* commit '6d07135b':
  separate transmission losses into axle and gearbox (sum file)

Merge pull request #267 in VECTO/vecto-sim from ~EMQUARIMA/vecto-sim:bugfix/VECTO-347-vecto-crashes-when-opening-engie-only to develop

* commit '884d90c7':
  vecto gui: open engine-only jobs, validate engine-only jobs on save; validate cycle data
  removed mod fiels for generic vehicles

Merge pull request #266 in VECTO/vecto-sim from ~EMQUARIMA/vecto-sim:feature/VECTO-346-update-generic-vehicles to develop

* commit '9349886a':
  removing mod-files and sum-files from repo
  handle the case when a file can't be opened
  adapt engine fld and map to technical annex
  make torque converter less efficient
  removing old generic vehicles
  added citybus vehicle with AT Gearbox
  adding generic vehicle (Coach) with AAUX
  bugfix: peaks in fuel consumption due to resetting total FC during simulation (init gear)
  corrected ouput to match unit in column header
  bugfix: fuel density
  New generic vehicle for PTO Cycle
  fix: relative path for aaux file
  remove cast to single for gearbox ration in list-view
  save engineering files in engineering mode (gbx)
  adding new generic vehicles for enineering & declaration mode: Truck Class 2 & Class 5
  removed no-longer needed properties
  removed 'skip gears' and 'early upshift' from input data and component data. only depends on shift stragety.
  Adding P_add input to GUI and JSON format
  more clear implementation of wheels class (confusion about dynamic tyre radius and wheel diameter), extending testcase

removed 'skip gears' and 'early upshift' from input data and component data. only depends on shift stragety.

more clear implementation of wheels class (confusion about dynamic tyre radius and wheel diameter), extending testcase

* commit '2ee2c78d':
  bugfix measuredspeed with gear (AT Model): use the same algorithm for searching operating point as in regular simulation, powertrainbuilder: use cyclegearbox