Add @TomlIgnore and @TomlComment annotations

[ErdbeerbaerLP]

I added two annotations to this library:

• @TomlIgnore
  
  Fields with this annotation will not get written to the toml file.

• @TomlComment
  
  When adding this annotation to an field, the value of this annotation will get written as comment above the toml entry

Example:

public class SomeConfig {
   @TomlIgnore
   public int secretInteger = 42;

   @TomlComment("This is an comment")
   public String key1 = "value1";

   @TomlComment({"This is an", "multilined comment"})
   public String key2 = "value2";

   @TomlComment("This is also\nan multilined comment")
   public String key3 = "value3";
}

Written to toml file using TomlWriter:

# This is an comment
key1 = "value1"
# This is an
# multilied comment
key2 = "value2"
# This is also
# an multilined comment
key3 = "value3"

Need another use example? I already used it here to create an configuration file

[Dragon-Seeker]

I honestly would love for this PR to get merged as it would be great to have comments thru annotations. It seems to work for my case as i'm currently using it to generate config files for a game without issue

[stjepanmamusa]

I'd like to see this merged also, I'm writing a config generator for InfluxData Telegraf Monitoring agent, and these would help a lot.
@mwanji any updates on this being merged?