Implement skip operator
Add tests for skip operator
Sort the list of operator test files
Move tests for take_until to separate file
Implement skip_until operator
Add tests for skip_until operator
Fix state transition on take_until

and add comments to states to facilitate reading in future
Repair GCC compilation
Add tests for operators

buffer, distinct_until_changed, scan, switch_on_next
Merge pull request #15 from ValeriyKopylov/new_operators

New operators
Merge pull request #17 from ValeriyKopylov/operators_test

Add tests for operators
add as_dynamic, remove incorrect coordination of subscriber
more work on coordination
add println utility
rename synchronize to publish_synchronize
cleanup alias'
add observe_on

still has at least one race condition
fix crazy subtle concurrency bug

returning an observer instead of a subscriber. caused a break in the
lifetime nesting that due to tests referencing stack vars caused weird
stack stomping.
connect coordinators to subscriber lifetime
fix deadlock, error and dispose