agent: Document and implement cancelling of restjson requests.

Fixes #372
Closes #344

Reviewed-by: Stef Walter <stefw@redhat.com>
web: Tell the channel when a restjson request is cancelled.

Fixes #372
Closes #444

Reviewed-by: Stef Walter <stefw@redhat.com>
daemon: Fix invalid memory accesses in resource monitors.

Wrap the index correctly in GetSamples and don't run it in a thread.
The samples can not be read from multiple threads.

Closes #449

Reviewed-by: Stef Walter <stefw@redhat.com>
WIP Revert "tools: Make tap-gtester more compatible with older python"

This reverts commit 7119fa99a8a0e391a6156ec33409d69cab8706b4.
WIP More fixes for travis
Merge branch 'master' into travis-memory