Allow higher unicode characters in XMB files.

Allow higher unicode characters in XMB files.

The XMB tool has a regex of invalid XML characters, which erroneously
contained all unicode characters in the supplementary planes (U+10000 to
U+10FFFF). The tool would silently replace these characters with spaces
when generating XMB files, which caused problems recently when an emoji
character was added to a grd file. The translation console supports
these characters, so GRIT should too.

The XMB tool now supports these characters, and now raises an exception
if an invalid character is used (instead of silently replacing it with a
space).

BUG=498288
Committed: https://crrev.com/96a915e2679355c93d458699c49b365f0a05c27d
Cr-Commit-Position: refs/heads/master@{#359621}

[newt (away), 2015-11-13 17:48:30]

newt@chromium.org changed reviewers:
+ thakis@chromium.org

[newt (away), 2015-11-13 17:48:30]

PTAL (third time's the charm)

[newt (away), 2015-11-13 17:48:50]

The CQ bit was checked by newt@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-11-13 17:49:18]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1440313003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1440313003/1

[Nico, 2015-11-13 17:59:07]

lgtm

[commit-bot: I haz the power, 2015-11-13 19:13:23]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-11-13 19:13:24]

Dry run: This issue passed the CQ dry run.

[newt (away), 2015-11-13 19:20:41]

The CQ bit was checked by newt@chromium.org

[commit-bot: I haz the power, 2015-11-13 19:21:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1440313003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1440313003/1

[commit-bot: I haz the power, 2015-11-13 20:26:53]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-13 20:28:16]

Patchset 1 (id:??) landed as
https://crrev.com/96a915e2679355c93d458699c49b365f0a05c27d
Cr-Commit-Position: refs/heads/master@{#359621}