* tests: update to cope with go1.7 SSA compiler
* de-vendored golang.org/x/debug/dwarf
We need our own tweaked version
* dwarf/debug/dwarf: always use the entry's name attribute
Using the name attribute leads to better type names as well as fixes
inconsistencies between 1.5, 1.6 and 1.7.
* proc: Updated loadInterface to work with go1.7
go1.7 changed the internal representation of types, removing the string
field from runtime._type.
Updated loadInterface to use the new str field.
Breakpoints, tracepoints, etc.. take a location spec as input. This
patch improves the expressiveness of that API. It allows:
* Breakpoint at line
* Breakpoint at function (handling package / receiver smoothing)
* Breakpoint at address
* Breakpoint at file:line
* Setting breakpoint based off regexp
