Releasing v4.2.0

* Refactored cell & formula logic out into separate files
* Added more tests to test things independently.

t/formula.vim

@@ -0,0 +1,41 @@
+" vim: fdm=indent
+source t/config/options.vim
+
+call vspec#hint({'scope': 'tablemode#spreadsheet#formula#scope()', 'sid': 'tablemode#spreadsheet#formula#sid()'})
+
+describe 'Formulas'
+  describe 'Add Formula'
+    before
+      new
+      read t/fixtures/formula/sample.txt
+    end
+
+    it 'should add a formula successfully'
+      call cursor(6, 15)
+      call tablemode#spreadsheet#formula#Add("Sum(1:4)")
+      Expect tablemode#spreadsheet#cell#GetCell() == '125.0'
+      call cursor(8, 15)
+      Expect getline('.') == '/* tmf: $5,2=Sum(1:4) */'
+
+      call cursor(7, 15)
+      call tablemode#spreadsheet#formula#Add("Sum(1:-1)")
+      Expect tablemode#spreadsheet#cell#GetCell() == '250.0'
+      call cursor(8, 15)
+      Expect getline('.') == '/* tmf: $5,2=Sum(1:4) ; $6,2=Sum(1:-1) */'
+    end
+  end
+
+  describe 'Evaluate Formula'
+    before
+      new
+      read t/fixtures/formula/formula.txt
+    end
+
+    it 'should evaluate the formula successfull'
+      call cursor(6, 15)
+      call tablemode#spreadsheet#formula#EvaluateFormulaLine()
+      Expect &modified == 1
+      Expect tablemode#spreadsheet#cell#GetCell() == '125.0'
+    end
+  end
+end