v0.3.6

MemPool v0.3.6

Diff since v0.3.3

Closed issues:

• bad ccall is causing segfaulting on master (#52)

Merged pull requests:

• Add approx_size for String and Symbol (#47) (@DrChainsaw)
• Add == and hash for DRef (#50) (@jpsamaroo)
• fix #52, bad ccall with julia v1.7 (#53) (@JeffBezanson)
• fix finalizer task switch (#54) (@krynju)