Feature release: delayed initialization of the memory pool

IMPORTANT: backward-incompatible changes ahead:

• Change the default ctor for boost_intrusive_pool: it's not allocating anymore a pool with the default size; rather it constructs a completely empty pool and it's mandatory to use the (new) init() method afterwards. Due to this change the MAJOR version of this project will be bumped from 1 to 2.

Release 1.3

Add support for bounded-size memory pools, which return an invalid boost intrusive pointer when their max size is reached.

Release 1.2

Just add support for 2 debug preprocessor symbols:

• BOOST_INTRUSIVE_POOL_DEBUG_CHECKS=1 to help debugging generic memory pool consistency
• BOOST_INTRUSIVE_POOL_DEBUG_THREAD_ACCESS=1 to help debugging multithread accesses

Release 1.1

First stable release, tested in production.

Version 0.1

First release