Added test case for #91 and fixed a bug. This and previous commits are

also related to #59. Close #91

src/main/java/com/github/sommeri/less4j/core/parser/TermBuilder.java

@@ -104,6 +104,7 @@ private Expression buildFromColorHash(HiddenTokenAwareTree token, HiddenTokenAwa
     if (parsedColor==null) {
       FaultyExpression faultyExpression = new FaultyExpression(token);
       problemsHandler.notAColor(faultyExpression, text);
+      return faultyExpression;
     }
 
     return parsedColor;

src/test/resources/command-line/errors.css

@@ -0,0 +1,4 @@
+.test h4 {
+  declaration: !#error#!;
+  padding: 2 2 2 2;
+}

src/test/resources/command-line/errorsandwarnings.css

@@ -0,0 +1,4 @@
+{
+  declaration: !#error#!;
+  padding: 2 2 2 2;
+}

src/test/resources/compile-basic-features/functions/colors.less

@@ -63,3 +63,4 @@
     color: blue2;
     border: 2px solid superred;
 }
+

src/test/resources/error-handling/unparseable-color.css

@@ -0,0 +1,3 @@
+#ugly {
+  color: !#error#!;
+}

src/test/resources/error-handling/unparseable-color.err

@@ -0,0 +1,2 @@
+Errors produced by compilation of testCase
+ERROR 2:10 The string "#white" is not a valid color.

src/test/resources/error-handling/unparseable-color.less

@@ -0,0 +1,3 @@
+#ugly {
+  color: #white;
+}