common: add requirement for unlimited virtual memory

Some tests fail if overcommit is disabled and virtual
memory is limited due to large memory requirements.
Such tests can require both overcommit enabled and
unlimited virtual memory.
blk: reduce the minimum BTT size to 16MB

Reduce the minimum BTT size to 16MB
and the libpmemblk minimum size to 16MB+8KB.
Update two unit tests.
Merge pull request #88 from ldorau/blk-reduce-the-minimum-BTT-size-to-16MB

blk: reduce the minimum BTT size to 16MB
Merge pull request #87 from plebioda/fix-overcommit-memory-issue

common: add requirement for overcommit memory in unittests
vmem: make sure a pool is destroyed

Make sure that a destroyed pool cannot be reused.

Ref: pmem/issues#20
Merge pull request #90 from ldorau/vmem-destroy-pool_id-in-pool_destroy

vmem: make sure a pool is destroyed
vmem: remove unnecessary assert in vmem_free()
Merge pull request #91 from krzycz/vmem-null_free

vmem: remove unnecessary assert in vmem_free()
common: fix run tests by superuser
vmem: fix dependencies on jemalloc library

Automatically rebuild libjemalloc and libvmem in case of any change
in jemalloc source code.
Merge pull request #94 from krzycz/vmem-jemalloc_dep

vmem: fix dependencies on jemalloc library
common: link to libpthread
Merge pull request #93 from spawlows/common-util-fix-tests-by-root

common: fix run tests by superuser
Merge pull request #92 from krzycz/common-libpthread

common: link to libpthread
tools: pmempool utility

- pmempool utility with the following commands:
-- create - creating pool files
-- info - parsing pool files
-- dump - dumping data from pool files
-- check - checking and repairing pool files
- update scripts for creating packages
- bash completion script
- manual pages and README file