Migrated argument check tests to arguments.R
Migrated dgCMatrix tests to dgCMatrix.R
Migrated vector tests to vector.R
Migrated matrix tests to matrix.R
Migrated array tests to array.R
Migrated complex tests to complex.R
Migrated tests of matio test datasets to matio_test_datasets.R
Migrated tests of character strings to strings.R
Migrated tests of structure arrays to structure.R
Migrated tests of cell arrays to cell.R
Migrated tests of logical values to logical.R
Remove empty and unused file

* inst/tests/test_rmatio.r: Removed, all tests are now in folder tests/
Removed usage of testthat when testing the package