should wsk action invoke be blocking by default?

[rabbah]

today wsk action invoke is asynchronous and one must do -b or -r to get a blocking activation --- it seems that almost always when developing and testing the common case is for a blocking invoke.

should we flip the default and add -a for async?

[csantanapr]

but don't error if they specify -b or -r to be backwards compatible?

there would be a new flag for async?

[csantanapr]

there would be a new flag for async?
duh

should we flip the default and add -a for async?

[rabbah]

correct -b and -r are preserved (-r still makes sense anyway because it produces a different out than -b) and a new flag --async|-a for the async case.