Add the characters <>`^ to the alt-sym dialog.

The G2's keyboard lacks a number of special characters:

    ` ^ [ ] { } \ | < >

Some of these are handled by the character picker that pops up when
pressing alt-sym (alt and the space bar) but not all. This change adds
the last few missing characters so it is now possible to access the full
qwerty character set when using the physical keyboard.

I am only familiar with the G1/G2 phones so I do not know what
characters other phones may be lacking. Long term it may be useful to
make this character picker customizable for each phone model. For now
this trivial patch is sufficient to make me happy.

Change-Id: I8d1592ae6731620c1eeacfce39fbae8443db6884