Some ItemStack nullability improvements

Merge pull request #53 from X00LA/1.10.x

Updated de_DE.lang

Merge pull request #53 from X00LA/1.10.x

Updated de_DE.lang

Fixed canToolHarvestLevel, Closes #49

Updated Forge to add support for new getHarvestLevel
Added mod name to @mod annotation
Cleanup of a few unused parameters in method constructors

[Feature] Added names instead of numbers for harvestlevels (#48)

Fix TiC harvest level name integration and add harvest level names to tooltips

Port to 1.9

Add Waila option to show harvest level number

 * Can now choose to show harvest level name, number, both, or neither
 * Only shows the number + name if they are different
 * Closes #41

Use Forge's metadata-specific getDigSpeed method to check effectiveness

 * Closes #38

Fix GregTech harvestability info

 * The disguise code was getting in the way
 * Fixes #28

Update build instructions