post work bump() logic

[guruofquality]

When a work session completes, we need to choose when to bump the work handler again:

• always bump for source blocks
• bump after consumption/production
• bump after outputport popbuffer
• bump after inputport setreserve

[guruofquality]

everything but the set reserve: https://github.com/pothosware/pothos-library/commit/ba037641e13da58610ede0c81ccf3195fe44a564

[guruofquality]

• call yield in set reserve: https://github.com/pothosware/pothos-library/issues/39
• bump also after user make yield() call

[guruofquality]

• added bump flag to set reserve: https://github.com/pothosware/pothos/commit/08d7131095a74b23ae744148de1946a2c0626f90