Version 1.21

- FIX: Prevent script errors when the error message containing the full command line from a failing vimtest#System() contains characters like ['"()].
- CHG: Drop comma in the lists of failed / skipped / errored test and add .vim extension, so that the file list can be copy-and-pasted to another runVimTests invocation or :argedit'ed in Vim.
- CHG: Change default mode from "user" to "default"; this is what I use all the time, anyway, as the "user" mode is too susceptible to incompatible customizations.
Version 1.22

- Include the version 1.21 changes in the Windows runVimTests.cmd, too.
- Switch to Git for the plugin's development to prevent such omissions (caused by my manual syncing, which is more complex in this case with files distributed over many different directory trees).