Added defalt .drone.yml
Added the correct commands to script
Fixed typo
Removed .travis.yml
Updated docker image name and added paper build
Add: ht/common.h with debug helper macro
Added ht/common.h header
Added debug output: ht_init()
Added debug output: ht_destroy()
Added debug output: ht_del()
Added debug output: ht_find()
Added debug output: ht_ndel()
Added debug output: ht_insert()
Merge pull request #221 from matthiasbeyer/add-debug_output_ht

Add debug output for hashtable implementation
Merge pull request #222 from TheNeikos/add-drone_support

Add drone support
Fix: avl_get_hash() should get a const param
Fix: avl_height() should get const arg
Fix: avl_node_cnt() should get const arg
Merge pull request #236 from matthiasbeyer/fix-const_args_avl

Made some avl function parameters const
Fix: Warn on unused linked list function call return values