Bug fix for windows file paths

lib/app.js

@@ -8,6 +8,8 @@ const getInstrumentedVersion = require('./instrumentSolidity.js');
 const CoverageMap = require('./coverageMap.js');
 const defaultTruffleConfig = require('./truffleConfig.js');
 
+const isWin = /^win/.test(process.platform);
+
 const gasLimitHex = 0xfffffffffff;               // High gas block limit / contract deployment limit
 const gasPriceHex = 0x01;                        // Low gas price
 
@@ -111,7 +113,9 @@ class App {
           this.log('Instrumenting ', file);
           currentFile = file;
 
-          const contractPath = path.resolve(file);
+          const contractPath = isWin
+            ? path.resolve(file).split('\\').join('/')
+            : path.resolve(file);
           const working = this.workingDir.substring(1);
           const canonicalPath = contractPath.split('/coverageEnv').join(working);
           const contract = fs.readFileSync(contractPath).toString();