Add support for different regex parsers

hsregex/build.gradle

@@ -0,0 +1,28 @@
+// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+plugins {
+    id 'java-library'
+}
+
+group 'org.pgpainless'
+
+repositories {
+    mavenCentral()
+    mavenLocal()
+}
+
+dependencies {
+    testImplementation "org.junit.jupiter:junit-jupiter-api:$junitVersion"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
+
+    implementation(project(":pgpainless-core"))
+
+    // Henry Spencers Regular Expression (RegEx packets)
+    implementation 'com.basistech.tclre:tcl-regex:0.14.5'
+}
+
+test {
+    useJUnitPlatform()
+}