* Added info on focus/ignore/show/hide to legend on graphs

* Made separate function for formatting filters in legend

Mainly use imported structs by field and update a mismatch printf
string on a test error message.

Skip TestSymbolizationPath (seems too Unix-specific).
Fix others with golden output to adjust for Windows file name syntax.

Instead of putting a pretty-printed string on the function.name,
populate the function.name, .file and location line with the
information from the node. This will help more easily extract this
information.

Also add some cachign to reuse functions and added a small test.

When using the call_tree option and generating a graph for kcachegrind,
it will merge back nodes that are distinct on the tree, producing some
confusing results. Add a suffix so that these entries are kept separate.

This addresses the problem described in
http://yosefk.com/blog/how-profilers-lie-the-cases-of-gprof-and-kcachegrind.html ,
particularly the summary "Choosing a profiler is hard" section.

When reconciling samples, cleanup file paths to allow functions to be
combined if their source filenames match after cleanup (eg "src.cpp" and
"./src.cpp").

Also clean up existing uses of filepath to avoid passing empty strings
to it: filepath.Base("") returns "."

Also update the build instructions to use go get