Use proper logging library

[NebelNidas]

Replaces all System.out calls with usages of a proper logger library.
Initially I wanted to use SLF4J's API with Log4j as implementation, but I couldn't get it to work with the Java module system, so I just used Log4j's API as well. Now uses SLF4J as API and Tinylog as implementation.
Also fixes some inconsistent capitalization of logged sentences.

[liach]

Instead of using apache with those unnecessary and bug-prone "features", how about we use System.Logger and System.getLogger instead, available since JDK 9?

[NebelNidas]

On second thought (and after seeing its JAR size), I agree that Log4j is indeed overkill for Matcher. I'm not a huge fan of System.Logger though, and since I want to split Matcher into a core (Java 8 based) and a gui (Java 17 based) module later down the road, using Java 9 features wouldn't work out anyway. I think I'm going to go with SLF4J and Tinylog for now

[liach]

On second thought (and after seeing its JAR size), I agree that Log4j is indeed overkill for Matcher. I'm not a huge fan of System.Logger though, and since I want to split Matcher into a core (Java 8 based) and a gui (Java 17 based) module later down the road, using Java 9 features wouldn't work out anyway. I think I'm going to go with SLF4J and Tinylog for now

Downgrading Matcher from Java 17 to 8, which already has premier support ended, isn't quite a good idea.

Matcher/build.gradle

Lines 36 to 45 in f01ed5a

	java {
	sourceCompatibility = JavaVersion.VERSION_17
	targetCompatibility = JavaVersion.VERSION_17
	if (!JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_17)) {
	toolchain {
	languageVersion = JavaLanguageVersion.of(17)
	}
	}
	}

Your code using matcher directly should migrate to Java 17. 8 is sweet for those sun package stuff and unrestricted reflection to change final fields, but you shouldn't have relied on them in the first place.

[NebelNidas]

I completely forgot that Matcher uses the Java module system already, so yeah, I should target Java 11 instead. I don't want to force library consumers into requiring Java 17 just yet, especially since Matcher's core functionality doesn't use any Java 12+ features anyway. Player can always bump it later if required.