symbol plugin does not cache

[elementaryBot]

When I close Scratch and re-open it, the symbols have to be reloaded for each file. We should save this data, at least as long as the tab is left open.

Launchpad Details: #LP1431087 Daniel Fore - 2015-03-12 00:41:58 +0000

[jeremypw]

@danirabbit Is this really worthwhile now? The delay in loading in most cases is minimal. We would need to decide where and how to cache the symbols and this would add significant complexity.

[jeremypw]

Also the file may have been edited elsewhere while Code was closed so the cached symbols may not be valid so they would have to be timestamped as well.