* base.R (write_keyval_file): New function.

* resources.R (METFRAG_ADDUCT_SWITCHES): Fix a typo.

* state.R (new_runtime_state): Update results with the new field
`subpaths'. Also, opted for relative vs absolute paths, because the
latter do not play well with tests in (stochastic) temporary
directories.

(base_conf): Update result to have a class `conf' signature.

(metfrag_conf): Update with new parameters.

(new_conf): Update with a call to `metfrag_conf'.

(write_metfrag_config): New function which writes the MetFrag config
file.

* tests/testthat/test-metfrag.R: New file with MetFrag tests.

* tests/testthat/_snaps/metfrag.md: New file .

Values and units have not been read in the GUI template correctly. Now
fixed.

* app<numeric/unit inputs>: Updated. Read in values/units properly.

* base(get_val_unit): New exported function.

* shiny-ui-base<everything related to order_summ table>: Commented
out. Too unstable for now.

* R/resources.R(SYM_YES,SYM_NO): New parameters.

R/base.R(yesno2log,log2yesno): New functions. Convert between logical
and factor Yes/No arrays.

fixlog2yesno: New function. Factorless version of log2yesno.

R/base.R(file2tab): Updated. Different NA defaults.

* R/base.R(gen_uniq_lab): New function.

* R/mix.R(read_conf): Moved from api.R and updated. Now generates
  random names for the files in compound lists. This was needed
  because in its reactive form, a list of reactives needs names.

* R/resources.R(EMPTY_CONF): New parameter. Skeleton conf object.

*R/api.R,R/base.R,R/mix.R <assert>: New function assert. Replaces
 assertthat:assert_that with shiny compatible validation.

* R/base.R (tab2file,file2tab): Return and write data.table objects.

(print_table): New function. Prints a data frame, or a table nicely.

One can switch the project, do the extraction, but: the status lamps
are wrong (previous project) and plots throw errors.