updated toy_example including the trench "Ettlinger Linie"

I removed the zero phase option from the code, due to complications depending on the source signal and the time window. However, from a technically point of view it was implemented right.

Position 7 in workflow is now F_HIGH_PASS.
All other parameters have been shifted.

I switched the naming of the variables of the frequency filtering to a more clear and easy one.
The change affects the JSON input file and the code itself.
The following renaming is used:
FC_START -> F_LOW_PASS_START
FC_END   -> F_LOW_PASS_END
FC_INCR  -> F_LOW_PASS_INCR
FC_EXT   -> F_LOW_PASS_EXT
FC       -> F_LOW_PASS
F_HP     -> F_HIGH_PASS

However, old JSON files will also work for now. If one of the old variables is not found, IFOS will search for the corresponding old one. This option will be removed in a future release.

All new files and folder in the par folder will be ignored from git.
This is usefull, as there is no big development inside the par folder. However, all production runs will produce a lot of files inside par, which are never needed to be under version control.

Implemented an offset based tracekill for STF.
Makefile in par folder has now two new targets:
1. make install, do an install from precompiled files
2. make reinstall, do a clean install

(1.) IFOS Makefile
Introduce dependencies files, which contain dependencied of each objective file. Therefore, it is possible to allow a more accurate rebuilt of the objective files.
New standard target is IFOS2D. Moreover a new target install is available.

(2.) Contrib
Fixed the problem with the dependencies files if the hole IFOS folder is copied over to a different hardware architecture.
You may now the error by ".d" files.

IFOS is now able to read in input files, that are formatted according the JSON standard. Nevertheless, the old files will work as well.

In addition, I fixed some compiler warnings.

Changed naming convention of individual spatial tapers for gradients, updated to usage with WORKFLOW

Merge STF_SH into development

INVMAT - > FORWARD_ONLY
INVMAT1 - > PARAMETERIZATION

Adding a few gitignore files to smooth the GIT workflow

! IFOS -> IFOS2D !
- New make targes is IFOS2D
- Generated binary is IFOS2D

Adding 2D to IFOS to indicate, that it is our 2D FWI Code.

Renaming:
QUELLART     ->  SOURCE_SHAPE
QUELLTYP     ->  SOURCE_TYPE
QUELLTYPB   ->  ADJOINT_TYPE
DAMPING       ->  VPPML

! This commit renames DENISE to IFOS !
Keep care and update all of your self written shell scripts etc.
The make target is 'IFOS' (capital letters).
The resulting binary is called 'IFOS' as well.

Now it is possible to specify WOLFE_C1_SL and WOLFE_C2_SL in the JSON input file.
Documentation is updated as well.
Smaller output improvements.

Removed TIME_FILT==1 from SH toy example

Workflow file now includes a header.

Updated documentation to include all new variables which are available in the JSON input file.

Update: Merge test

-Remove src_relicts
-Clean up of the Makefile in src/

adjustment of acoustic toy-example, scaling of the elastic explosive source and acoustic free surface condition.