Add `__repr__` to `Request` and `Result`

(cherry picked from commit 9754c7552d76c7769056a9e39511df0ac20eaa3c)
Signed-off-by: Nicolas Trangez <ikke@nicolast.be>
Raise `NotConnectedError` instead of generic `RuntimeError`

(cherry picked from commit 063b1cc4f5e1c1603b4e4b3c6f304776358520dd)
Signed-off-by: Nicolas Trangez <ikke@nicolast.be>
Add support for `AssertExists` sequence steps

(cherry picked from commit 7c620469d8ef6558def0ee6a30b83ef6607c8afa)
Signed-off-by: Nicolas Trangez <ikke@nicolast.be>
Implement `collapse_tlog`

(cherry picked from commit 3b9345aff3627ec262aea9581a7c856eebb0e9a1)
Signed-off-by: Nicolas Trangez <ikke@nicolast.be>
Add `replace` call

(cherry picked from commit 77306ebcc7dd65f6df52dbf144737104175b1765)
Signed-off-by: Nicolas Trangez <ikke@nicolast.be>

Conflicts:
	pyrakoon/client/__init__.py
	pyrakoon/client/sharding.py
	pyrakoon/protocol/__init__.py