v0.3.0

Changelog

• fix panic when linking to/from non-existent nodes
• fix broken import command
• add dotted lines for nodes with multiple parents
• add [*] completion state
• change Makefile PREFIX from /usr to /usr/local

Note: this release changes the default install location from /usr/bin/grit to /usr/local/bin/grit. If you've installed grit before using make install, you may need to delete the previous version to avoid conflicts.