Expose more convenience functionality in the python classes.

lldb.SBValueList now exposes the len() method and also allows item access:

lldb.SBValueList[<int>] - where <int> is an integer index into the list, returns a single lldb.SBValue which might be empty if the index is out of range
lldb.SBValueList[<str>] - where <str> is the name to look for, returns a list() of lldb.SBValue objects with any matching values (the list might be empty if nothing matches)
lldb.SBValueList[<re>]  - where <re> is a compiles regular expression, returns a list of lldb.SBValue objects for containing any matches or a empty list if nothing matches

lldb.SBFrame now exposes:

lldb.SBFrame.variables => SBValueList of all variables that are in scope
lldb.SBFrame.vars => see lldb.SBFrame.variables
lldb.SBFrame.locals => SBValueList of all variables that are locals in the current frame
lldb.SBFrame.arguments => SBValueList of all variables that are arguments in the current frame
lldb.SBFrame.args => see lldb.SBFrame.arguments
lldb.SBFrame.statics => SBValueList of all static variables
lldb.SBFrame.registers => SBValueList of all registers for the current frame
lldb.SBFrame.regs => see lldb.SBFrame.registers

Combine any of the above properties with the new lldb.SBValueList functionality
and now you can do:

y = lldb.frame.vars['rect.origin.y']

or

vars = lldb.frame.vars
for i in range len(vars):
  print vars[i]

Also expose "lldb.SBFrame.var(<str>)" where <str> can be en expression path
for any variable or child within the variable. This makes it easier to get a
value from the current frame like "rect.origin.y". The resulting value is also
not a constant result as expressions will return, but a live value that will
continue to track the current value for the variable expression path.

lldb.SBValue now exposes:

lldb.SBValue.unsigned => unsigned integer for the value
lldb.SBValue.signed => a signed integer for the value

llvm-svn: 149684