* Potential fix to #1626. Fixed typo is Makefile.
* Completed fix to #1626.
Summary:
changed 'error' to 'bail' in start_pageserver and start_safekeeper.
* Add a test case for reading historic page versions
Test read_page_at_lsn returns correct results when compared to page inspect.
Validate possiblity of reading pages from dropped relation.
Ensure funcitons read latest version when null lsn supplied.
Check that functions do not poison buffer cache with stale page versions.
This change brings the following improvements to our build system:
* Now BUILD_TYPE also affects rust apps.
* From now on, cargo will respect `-jN` passed via `make`. However, note
that `rustc` may spawn multiple threads depending on compile flags.
* Cargo is able to cooperate with make to better schedule parallel jobs,
which leads to better build times (-20s in release mode on my machine).
Previously, typos like `BUILD_TYPE=rlease` would silently
lead to building debug binaries. The current approach is also
more future-proof, since we might add `profile`, `valgrind`
as well as other build types.
