v0.8.7

1. Added icon to context menu entry (usage).
2. Added wstartex subcommand to cmdtool (usage).
3. Added mintty_options and keep_wsl_running options to etc/wsl-terminal.conf (usage).

If your wsl-terminal version number is higher than 0.8.0, can upgrade it with ./cmdtool update (usage).

sha256sum	filename
dda95754b1329676199b8299b01c88aaa3cd694e67a472bbcfa8a84aa2725a87	wsl-terminal-0.8.7.7z
bfcd19bfd2d370e950a4c6f378e7ef72d60e9b8ebf99d0af4d4bcc7f48810d17	wsl-terminal-0.8.7.zip