wx: Only call XInitThreads for linux

Turns out OSX also returns 'posix' for os.name. This limits it to
linux only. Note that it's purely cosmetic because on OSX it would
just print a warning but not prevent anything from working.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
wxgui: Make sure to only start the flow graph once all init is done

Currently we start the flow graph in the stdframe constructor.
However at that point, the frame isn't attached to the app and it's not
"shown" yet which means some UI operations can still fail.

This is a race condition which happens on OSX. You can reproduce it on
linux as well by adding a sleep(1) after starting the flow graph.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
volk: adding volk_malloc and volk_free functions to handle allocation of aligned memory.
filter: switched from using fft::malloc to volk_malloc.
qtgui: switched from using fft::malloc to volk_malloc.
build: fixed a warning on OS X.
Merge branch 'maint'
Merge branch 'volk_malloc'
build: of course this wouldn't have worked. Now fixing the compiler warning on OS X.
Merge branch 'maint'
grc: fix report window auto-scrolling
grc: adding a page that captures and stores some XML parsing errors
grc: xml parser errors dialog fixes and refactoring
grc: detect block (category) tree files by name (not by trail and error)
grc: show xml parser error warning in report window
grc: renaming flowgraph errors menu item and xml parser action
docs: Netwrok -> Network (satisfy OCD)
Merge remote-tracking branch 'gnuradio-wg-grc/grc_report_window_autoscroll_fix' into maint
Merge remote-tracking branch 'gnuradio-wg-grc/grc_xml_error_dialog'
Merge remote-tracking branch 'martin/docs-fix2' into maint