Add missed key definitions

This patch adds the keys for the keypad (in both modes, application mode or
ansi mode) and function keys. It uses the same convention than xterm and
instead of using the XK_Fxx values it generates them using F1-F12 and
modifiers. For example:

   F1 -> ^[OP
   F1 + Shift = F13 -> ^[[1;2P
   F1 + Control = F25 -> ^[[1;5P
   F1 + Mod2 = F37 -> ^[[1;6P
   F1 + Mod1 = F49 -> ^[[1;3P
   F1 + Mod3 = F61 -> ^[[1;4P

It is also important notice than the terminfo capability kIC (shifted insert
key) only can be generated using the keypad keyboard, because the shorcut
for selection paste is using the same combination.

After this path the number of elements in the Key array becomes high, and
maybe a sequencial search is not enough efficient now.
---
 TODO         |    6 +---
 config.def.h |  102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 st.info      |   70 ++++++++++++++++++++++++++++++++++++++--
 3 files changed, 169 insertions(+), 9 deletions(-)