fix suspend with cause bug (pingcap#16)

add SuspendStack support (pingcap#15)

add NewNoStackError support (pingcap#13)

Merge pull request pingcap#12 from lysu/dev-make-errors-trace-inline

errors: make errors.Trace mid-stack inlineable

Merge pull request pingcap#12 from lysu/dev-make-errors-trace-inline

errors: make errors.Trace mid-stack inlineable

add more juju/errors compatibility functions

Merge pull request pingcap#10 from gregwebs/docs-deprecation

update docs around deprecation

Merge pull request pingcap#9 from pingcap/reduce-alloc-print-stack

reduce allocations when printing stack traces (pkg#149)

add NewStack(), which generates a stack trace

release errors 0.8.0