v0.7.0

LifeContingencies v0.7.0

Diff since v0.6.0

Closed issues:

• Namespace pollution (#13)
• export APV (#28)
• API definitions - intervals vs n-payments (#30)

Merged pull requests:

• Expanded Annuity & Increase consistency with Literature (#31) (@alecloudenback)
• Update for MortalityTables v0.10 (#32) (@alecloudenback)
• Avoid namespace pollution by not exporting short-form notation (#33) (@alecloudenback)