hterm 1.9, nassh 0.18.19.1: Shift-Tab fix.

hterm 1.9: Fix issues with shift-key and CSI sequences.

* Clear e.shiftKey in hterm_keyboard_keymap.js' sh() function so that
  hterm_keyboard.js doesn't apply its own shift key munging.

nassh 0.8.19.1: Update to hterm 1.9

* Include Shift-Tab fixes from hterm 1.9.

BUG=None
TEST=Manual testing.
TEST=hterm_test.html, 66/66 tests passed.

Change-Id: Ie7fb275f162971f959e51f42670eda1ed913ba6c
Reviewed-on: https://gerrit.chromium.org/gerrit/59284
Reviewed-by: Marius Schilder <mschilder@google.com>
Commit-Queue: Robert Ginda <rginda@chromium.org>
Reviewed-by: Robert Ginda <rginda@chromium.org>
Tested-by: Robert Ginda <rginda@chromium.org>

• hterm/doc/changelog.txt[diff]
• hterm/js/hterm_keyboard.js[diff]
• hterm/js/hterm_keyboard_keymap.js[diff]
• nassh/doc/changelog.txt[diff]
• nassh/manifest.json[diff]