Add methods to specify size limits in bytes

The existing methods (`HTreeMapMaker#expireStoreSize(double)`, `DBMaker#sizeLimit(double)`) with the size limit in gigabytes as double sometimes felt a bit clunky when specifying limits less than 1 GB.

This changeset adds methods to specify these limits in bytes as a long value.

In order to not break backward-compatibility the methods for specifying the size limits in bytes have a suffix "Bytes", e. g. `DBMaker#sizeLimitBytes(long)` instead of overloading the original methods, e. g. `DBMaker#sizeLimit(double)`.