Improves conformance with the official test suite:
- W4TN (Spec Example 9.5. Directives Documents)
- 2LFX (Spec Example 6.13. Reserved Directives [1.3])
- 6LVF (Spec Example 6.13. Reserved Directives)
- S3PD (Spec Example 8.18. Implicit Block Mapping Entries)
- NHX8 (Empty Lines at End of Document)
- 2JQS (Block Mapping with Missing Keys)
- M7A3 (Spec Example 9.3. Bare Documents)
- WZ62 (Spec Example 7.2. Empty Content)
- 52DL (Explicit Non-Specific Tag [1.3])
- S4JQ (Spec Example 6.28. Non-Specific Tags)
- 8MK2 (Explicit Non-Specific Tag)
- R4YG (Spec Example 8.2. Block Indentation Indicator)
- 6BCT (Spec Example 6.3. Separation Spaces)
- A2M4 (Spec Example 6.2. Indentation Indicators)
- Q5MG (Tab at beginning of line followed by a flow mapping)
- S7BG (Colon followed by comma)
- DK3J (Zero indented block scalar with line that looks like a comment)
- FP8R (Zero indented block scalar)
- 4MUZ (Flow mapping colon on line after key)
- NJ66 (Multiline plain flow mapping key)
- UT92 (Spec Example 9.4. Explicit Documents)
- 9SA2 (Multiline double quoted flow mapping key)
- K3WX (Colon and adjacent value after comment on next line)
- 5MUD (Colon and adjacent value on next line)
Also adds the license file to nupkg to fix NU5125 warning.