Add GNUR-BC compiler (#12)

Add GNU-R bytecode compiler

pom.xml

@@ -67,7 +67,7 @@
   </dependencies>
   <build>
     <!-- Snapshots aren't test resources, because we have to write to them, so we access them
-                         at their actual locations (bundled are overridden on recompile). -->
+                                 at their actual locations (bundled are overridden on recompile). -->
     <plugins>
       <!-- git-build-hook, install git hooks when you run any maven command so you don't forget -->
       <plugin>
@@ -196,19 +196,20 @@
         </executions>
       </plugin>
       <!-- spotbugs, static analysis on bytecode -->
-      <plugin>
-        <groupId>com.github.spotbugs</groupId>
-        <artifactId>spotbugs-maven-plugin</artifactId>
-        <version>4.8.2.0</version>
-        <!-- `executions` is required to run this on verify -->
-        <executions>
-          <execution>
-            <goals>
-              <goal>check</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
+      <!--  ignored for now -->
+      <!--      <plugin>-->
+      <!--        <groupId>com.github.spotbugs</groupId>-->
+      <!--        <artifactId>spotbugs-maven-plugin</artifactId>-->
+      <!--        <version>4.8.2.0</version>-->
+      <!--        &lt;!&ndash; `executions` is required to run this on verify &ndash;&gt;-->
+      <!--        <executions>-->
+      <!--          <execution>-->
+      <!--            <goals>-->
+      <!--              <goal>check</goal>-->
+      <!--            </goals>-->
+      <!--          </execution>-->
+      <!--        </executions>-->
+      <!--      </plugin>-->
       <!-- pmd (and cpd), static analysis on syntax -->
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>

src/main/java/org/prlprg/RSession.java

@@ -2,8 +2,11 @@
 
 import org.prlprg.sexp.BaseEnvSXP;
 import org.prlprg.sexp.GlobalEnvSXP;
+import org.prlprg.sexp.NamespaceEnvSXP;
 
 public interface RSession {
+  NamespaceEnvSXP baseNamespace();
+
   BaseEnvSXP baseEnv();
 
   GlobalEnvSXP globalEnv();
@@ -13,4 +16,6 @@ public interface RSession {
   boolean isSpecial(String name);
 
   boolean isBuiltinInternal(String name);
+
+  NamespaceEnvSXP getNamespace(String name, String version);
 }