Merge pull request #17 from sharddith/master

Added XIRR Feature. XIRR determines the IRR for irregular intervals.

Merge pull request #17 from sharddith/master

Added XIRR Feature. XIRR determines the IRR for irregular intervals.

IRR: Throw error when at least one positive and one negative value wa…

…s not found and throw another error after 1000 tries

Merge pull request #10 from mmcdermott/irr-perf-improvements

Irr perf improvements

Merge branch 'master' of https://github.com/essamjoubori/finance.js

Update node version

Update README.md

Add IRR